THE EFFECT OF PREOPERATIVE INTRAAORTIC BALLOON PUMP SUPPORT IN HIGH-RISK PATIENTS REQUIRING MYOCARDIAL REVASCULARIZATION

The intra-aortic balloon pump (IABP) is an established additional supp ort to pharmacologic treatment of the failing heart after myocardial i nfarction, unstable angina and cardiac surgery. The physiologic effect s of IABP are: increased coronary perfusion and decreased left ventric ular outflow impendance. The effects of preoperative IABP are not esta blished. The aim of this study was to define indications and evaluate the effect of preoperative IABP support. Between January 1, 1990 and D ecember 31, 1994, 1999 patients underwent CABG [318 REDOCABG, 15.9% an d 1681 primary CABG, 84.9%]. From January to June 1994, 80 of 1811 pat ients (4.5) required additional intra-aortic balloon pump (IABP) suppo rt postoperatively, 35 after REDO (21%) and 45 after primary CABG, 3%. Indication for IABP was failure to wean from cardiopulmonary bypass ( CPB), despite maximal dose pharmacological support. The overall hospit al mortality was 11.6% after REDO's and 2.1% after primary CABG, p < 0 .001. In those where IABP was required the mortality rate was 67.7% af ter REDO and 36.8% after primary CABG, p < 0.01. Multivariate analysis identified preoperative unstable angina as independent risk factor fo r mortality (p < 0.001). REDO-CABG, LVEF < 40%, diffuse coronary arter y disease and left main stem stenosis were identified as riskfactors f or mortality when combined with one and another in a combination of at least two factors. In the IABP supported group mean ICU stay was 5.4 +/- 1.8 days. Thereafter the concept of preoperative use of LABP was i ntroduced and presence of at least two of the above identified riskfac tors served as indication for preoperative IABP treatment. The IABP wa s placed in the operating room at induction of anesthesia (1-1.5 hr pr ior to cross-clamping). Between June and December 1994, 19 of 188 pati ents received a preoperative IABP (9.0%). There were no balloon relate d complications. The mortality rate was 21%. Weaning from CPB was easy and in 30% of the cases the IABP was not necessary postoperative. In 90% of the pumps were removed within 24 hours postoperative. The mean Icy stay was 2.1 +/- 0.9 days. The first part of this study identified riskfactors for mortality after CABG and in the second series the eff icacy of preoperative IABP treatment in ''high-risk'' patients was dem onstrated. Preoperative IABP support in these patients seems also cost efficient due to lower mortality and shorter stay in intensive care u nit in this group of patients.